As the digital landscape for books increases, new entrants to the market are puzzled by its insistence on the ISBN. To many—particularly e-book—only publishers—it seems that the industry is insisting on using an antiquated standard. Why can't the ISBN be adapted to include suffixes that describe different formats? What use is the ISBN on the Web, where there are no bar codes? And how is this 13-digit number useful in a Google-driven discovery environment?

The job of the ISBN is to identify a book. Whether that book is a paperback, hardcover, PDF file, EPub file—if it's going to be sold in the book supply chain, it needs an ISBN to identify it.

Metadata is information about the book, such as title, author, format, edition, page count, price, publisher name. The job of metadata is to describe a book.

The ISBN is a flag; the metadata tells how to interpret that flag.

In the last two years, there has been a proliferation of e-books and e-book formats, and a tremendous increase in the number of independent publishers and self-published authors who are new to the industry. And the debate about how to use ISBNs for e-books has become surprisingly fierce. Many smaller publishers are reluctant to purchase large blocks of ISBNs to assign to each and every format of each and every e-book. It is costly; maintaining that metadata is also costly and time-consuming. Most publishers would like to see the industry standardizing around a single format of e-book.

The counter-argument is that if publishers do not assign ISBNs to each and every format of each and every one of their e-books, other parties will do that assigning for them: distributors, retailers, those whose e-commerce platforms are keyed off the ISBN. This makes tracking sales, vendor-of-record, metadata changes, and royalties vastly more complicated.

One proposed solution is to append the ISBN with a suffix that designates the e-book format. But this has many logical problems, not least of which is asking an identifier to do something it's not supposed to do: describe.

That is the job of the International Standard Text Code identifier (ISTC) that's rolling out this year. Its purpose is to identify a work (title, author) so that the book industry can then link a book to its many formats. An ISTC would link to many ISBNs. Each format would have a separate ISBN, some of which would be for e-books, some of which would be for physical books, some of which would be for audiobooks.

The ISBN uniquely and unambiguously identifies a book. It distinguishes large print, trade paper, hardcover, audio CD, downloadable audio, Kindle e-book, Barnes & Noble Nook, Sony e-reader, and all the other e-reader devices.

Why is this important? Because when a customer orders a book, it should be the right book. You don't want customers ordering a downloadable audio file under the impression that it is a CD audiobook or ordering the large print version of something when they really want a mass market paperback.

But where the ISBN truly gets interesting is in search.

The US ISBN Agency is run by R.R. Bowker, which also compiles Books in Print. BIP is a listing of all the books published in the U.S.; Bowker licenses BIP to a number of extremely important clients: Barnes & Noble, Borders, thousands of libraries, the top three search engines, and many mobile clients.

If your book has an ISBN, it gets listed in BIP. If it's listed in BIP, it's findable online. If your book does not have an ISBN, it does not automatically appear in searches. (Yes, even Google.) It's anybody's guess how people are going to find it. It's entirely up to your own marketing efforts to get the word out.

BIP also has a bibliographic database that's available on the open Web (at This is regularly crawled by Google; if your book is not in that database, it doesn't get crawled along with all the others.

This is not to say that if you have an ISBN, you don't have to market your book. But it does mean that the hardest work—introducing a Web site to your title, the equivalent of a cold call—has already been done.